The magnetic field of earth is due to
Motion and distribution of some material in and outside the earth
Interaction of cosmic rays with the current of earth
A magnetic dipole buried at the centre of the earth
Induction effect of the sun
A line passing through places having zero value of magnetic dip is called
At a certain location in Africa, a compass points $12^o$ West of the geographic North. The North tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points $60^o$ above the horizontal. The horizontal component of the earth's field is measured to be $0.16\, G$. The magnitude of the earth's field at the location will be
Consider the plane $\mathrm{S}$ formed by the dipole axis and the axis of earth. Let $\mathrm{P}$ be point on the magnetic equator and in $\mathrm{S}$. Let $\mathrm{Q}$ be the point of intersection of the geographical and magnetic equators. Obtain the declination and dip angles at $\mathrm{P}$ and $\mathrm{Q}$
The angle of dip at a place on the earth gives
If the angles of dip at two places are $30^o$ and $45^o$ respectively, then the ratio of horizontal components of earth's magnetic field at the two places will be